It’s just brown treated spruce. And I lined the beds with 4 layers of black poly so the copper sulphate won’t leach into the soil. The bottom third of each bed is filled with rotten straw, for drainage and soil cost savings. The growing medium is 5/6 ProMix and 1/6 compost. This is year two. Next project is a composting system but we are moving to an acreage as soon as possible so I’m trying not to go too crazy building, because everything has to move. This project started out of a desire to go into last winter with as much food preserved as possible. I pressure canned 100 quarts of produce and meat last fall, and between that, dehydrated goods, vacuum sealed items, store bought preps and hunting kills, we finally have about three months of emergency provisions. I’m really trying to be ready for the upcoming shitstorm the government is no doubt orchestrating as we speak.